Fifth wheel coupling mechanism



June 2, 1953 F. H. KAYLER FIFTH WHEEL COUPLING MECHANISM 2 Sheets-Sheet 1 Filed Oct. 20, 1951 June 2, 1953 F. H. KAYLER 2,640,707

- FIFTH WHEEL COUPLING MECHANISM F iled Oct. 20, 1951 I 2 shets-s eet 2 D M Q my.

Patented June 2, I953 UNITED STATES PATENT OFFICE 2,640,707 FIFTH WHEEL COUPLING MECHANISM Frank H. Kayler, Alliance, Ohio, assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application October 20, 1951, Serial No. 252,350

Claims. 1

This invention relates to fifth wheels and more particularly to a novel fifth wheel coupling mechanism of the type disclosed in U. S. Patent 2,015,313, issued to Edmund P. K-inne. In coupling mechanisms of this type, pivotally interconnected front and rear jaws are supported for translatory movement as a unit along guide means which pivot the rear jaw upwardly to closed position as the jaws move forwardly and which accommodate pivotal movement of the rear jaw downwardly to open position as the jaws move rearwardly with respect to the fifth wheel. A look is customarily pivoted to the support structure on a substantially horizontal axis for pivotal movement downwardly to locked position with respect to the rear jaw when the latter is closed and for pivotal movement upwardly to unlocked position accommodating rearward movement of the jaws to open position thereof.

In prior art arrangements of this type, the lock in its unlocked position bears against an upwardly facing surface of the rear jaw when the latter is in its open position; and it has been discovered that occasionally the rear jaw does not drop to fully open position by gravity during an uncoupling action. Also the rear jaw is sometimes moved from fully open position to a partly closed position when the rear extremity of the fifth wheel is tilted downwardly as frequently occurs in uncoupled position. It has also been found that such accidental movement of the rear jaw to partly closed position may be the result of interference as, for example, with accumulation of dirt or snow therebeneath, or such movement may occur due to a jarring force on the supporting vehicle.

It has also been discovered that occasionally the rear jaw remains in such a partly closed position when the fifth wheel is tilted upwardly to level position preparatory to a coupling operation with the king pin of a towed vehicle such as a semitrailer. Thus under such conditions the rear jaw may be in a position above the point whereat the lower surface of the king pin will clear the rear jaw, in which case the king pin engages a rearwardly facing surface of the rear jaw moving it to closed position without effecting coupling of the king pin by the jaws.

In such prior art arrangements, use of a spring to urge the lock downwardly against the rear jaw in its open position tends to aggravate the tendency of the rear jaw to remain in a partly closed position, inasmuch as the spring pressure is effective to cause frictional and resilient resistance to movement of the jaw toward its fully open position.

Accordingly, a primary object of the present invention is to devise a fifth wheel coupling mechanism of the above described type, wherein means are provided for positively opening the rear jaw when the fifth wheel is tilted to level position, particularly, when the rear jaw has previously been forced to partly closed position with the wheel tilted downwardly.

A more specific object of the invention is to provide spring means for positively urging the rear jaw to its fully open position under all conditions when the lock is in unlocked position.

Another object of the invention is to provide spring means for urging the lock downwardly against a cam surface of the rear jaw formed and arranged to positively urge the latter to its open position.

The foregoing and other objects and advantages of the invention will become apparent from a consideration of the specification and the accompanying drawings, wherein:

Figure 1 is a perspective view of a preferred embodiment of the novel coupling mechanism applied to a conventional fifth wheel which :is illustrated in phantom lines;

Figure 2 is a side elevational view of the novel coupling mechanism in coupling relationship'with a king pin, the king pin and fifth wheel structure being diagrammatically illustrated for the sakeof clarity;

Figure 3 is a side elevational View similar to Figure 2 but showing the coupling mechanism in fully open position preparatory to a coupling operation;

Figure 4 is a side elevational view similar to Figure 3 but showing the rear coupling jaw pivoted upwardly slightly toward closed position;

Figure 5 is a side elevational view similar to Figure 4 but showing the rear jaw pivoted upwardly a maximum distance toward closedposition with the jaws in extreme rearward position;

Figure 6 is a side elevational view similar to Figure 5 but showing both jaws moved forwardly toward closed position, and

Figure 7 is a side elevational view similar to Figure -6 with the rear jaw pivoted downwardly a maximum distance toward open position.

Describing the invention in detail, a preferred embodiment of the novel coupling mechanism is illustrated in the perspective View of Figure l as applied to a conventional fifth wheel 2 pivoted on a substantially horizontal axis .as at 4 to a bracket 6 at each side of the fifth wheel, said brackets being adapted for attachment to the frame Tof a vehicle (not shown) such as-an automotive truck.

The novel coupling mechanism comprises front and rear jaws 8 and I0, respectively, pivotally interconnected to each other as at I2 on a sub stantially horizontal axis for translatory movement as a unit to closed position shown in Figure 2 and to open position shown in Figure 3; and it will be noted that these jaws are provided at opposite sides thereof with conventional guide lugs or flanges I4 and I6, respectively, for slidable movement along a conventional support and guide ledge I8 (Figures 2 to 7) defining the lower edge of a guide slot 29 receiving said lugs l4 and I6. The ledge I8 terminates at its rear extremity in a downturned portion 22 accommodating pivotal movement of rear jaw II! downwardly to its open position shown in Figure 3, as the jaws move rearwardly during withdrawal of a king pin 24 of a coupled vehicle such as a semi-trailer.

The rear jaw I is locked in the closed position of Figure 2 by a lock generally designated 26 and pivoted as at 28 on a substantially horizontal axis to the fifth wheel 2, said lock having one or more legs 30 projecting forwardly from said axis 28 for abutment as at 32 with rearwardly facing surfaces of the rear jaw III to lock the jaws in the closed position of Figure 2.

The lock 25 is resiliently biased to the locked position thereof shown in Figure 2 by spring means herein illustrated in the form of at least one compression spring 33 compressed between a leg 30 and an overlying surface of the fifth wheel 2, although it will be understood that other forms and combinations of springs may be utilized as disclosed in my copending application Serial No. 105,080, filed July 16, 1949, now Patent No. 2,621,056.

The lock 26 is pivoted upwardly to unlocked position by any desired conventional operating means such as those described in said copending application, whereupon the king pin 24 may be withdrawn from the position by forward movement of the fifth wheel 2 or by rearward movement of the king pin 24 whereupon the jaws assume the fully open position of Figure 3.

Under these conditions, each leg 30 of the lock bears along a downwardly tapered nose 34 thereof against a curved upwardly facing cam surface 36 of the rear jaw I G and contacts said surface at a point 38 rearwardly of the axis I2 to yieldingly hold the rear jaw Ill in fully open position under the force of the spring 33 which is compressed between the leg 30 and the fifth wheel 2.

Figure 4 shows the rear jaw I0 pivoted upwardly slightly from the fully open position of Figure 3 to a partly closed condition as may occur for the reasons heretofore discussed; and

' it will be noted that under the conditions of Figure 4, the king pin 24 is unable to clear thetop of the rear jaw I0 and therefore can not enter the front jaw 8 as is required for a coupling operation.

It is noted that under the conditions of Figure 4, the lock nose 34 contacts the cam surface 36 as at 40, a point which is substantially further from the axis I2 than the point 38 of said surface 36 which is engaged by the lock nose in the fully open position of Figure 3. Thus the spring 33 is under greater compression under the conditions of Figure 4 than in the fully open condition of Figure 3, whereby the spring 33 positively urged the rear jaw I0 downwardly from the position of Figure 4 to the fully open position of Figure 3 thereby insuring a successful coupling operation.

Figure 5 shows the rear jaw I 0 pivoted upwardly to the maximum closed position when the jaws are in their extreme rearward position. Under these conditions, the lock nose 34 engages the surface 36 at a point 42 disposed further from the axis I2 than the point 40 which is engaged by the lock nose 34 under the partly closed condition of Figure 4. For this reason it will be noted that the spring 33 is under still greater compression than under the conditions of Figure 4, whereby said spring acting against the cam surface 36 by means of the look nose 34 is effective to urge the rear jaw I0 from the position of Figure 5 to the fully open position of Figure 3. It may be noted that the rear jaw I0 in Figure 5 is in its position of maximum upward movement toward closed position under the illustrated conditions inasmuch as the lu I5 thereof is engaged with the upper margin of the slot 20. It will be noted from Figure 5 that if jaw II) should be accidentally moved to this position with wheel tilted down, and not forced from this position to full open position of Fig-v ure 3 when wheel is leveled for coupling, a positive failure to couple would result due to forward face of king pin flange 24 engaging corner of rear jaw top and forcing jaw assembly forward to closed and locked position of Figure 2 with king pin 24 remaining rearwardly of the rear jaw, instead of gripped between the front and rear jaws.

Figure 6 illustrates a condition similar to that of Figure 5 but with both jaws 8 and I0 moved partially forwardly toward the fully closed position of Figure 2, and with the rear jaw pivoted upwardly as far as possible. It will be noted this upward position possible with jaw assembly moved partially toward fully closed position is greater than under condition of Figure 5 so that if jaws were accidentally moved to this position with wheel tilted down and not forced from this to open position when wheel was tilted up for coupling, the flange of king pin 24 could engage even below top of rear jaw, and result in coupling failure with kin pin remaining back of rear jaw. The jaw, however, will not remain in this position to cause coupling failure since the lock nose 34 engages the cam surface 36 as at 44, a point spaced farther from the axis I2 than the point 38 whereby the sprin is under greater compression than in fully open position, Figure 3.

Figure '7 shows an intermediate position reached by the rear jaw II) in being opened from partly closed position of Figure 6 to full open position of Figure 3. In this position the rear jaw ID has been urged downward by expansion of spring 33 to the position where guide lug I6 of the rear jaw ID is engaged with the support I8 defining the lower margin of the guide slot 23. Under these conditions, the lock nose 34 bears against the cam surface 36 as at 43, a point closer to the axis I2 than point 44 and farther from the axis I2 than point 38,

whereby the spring 33 and lock nose 34 acting against the cam surface 36 are effective underthe conditions of Figure 7 to pull the jaws 8 and I0 rearwardly and to pivot the rear jaw I0 downwardly to the fully open position of Figure 3.

Thus, it will be understood that the cam surface 36 is so formed and arranged as to curve continuously away from the axis I2 as said surface extends rearwardly therefrom, whereby any movement of the rear jaw II! from the fully open position of Figure 3 to a partly closed position is resisted by increasing compression of the spring 33 which thus positively urges the jaw H] from any partly open position thereof to the fully open position of Figure 3 ensuring success of the coupling operation.

It may be further noted that the effectiveness of the above described arrangement is facilitated by the fact that the contact of the lock nose 34 with the surface 36 is always at a point at least per cent closer to the pivotal axis 28 of the lock than the distance between the axis 28 and the axis [2, so that the pressure of the lock against the surface 36 is substantially rearwardly of the axis I2 to urge the jaw 19 downwardly about said axis 12.

I claim:

1. In a fifth wheel coupling mechanism; the combination of front and rear jaws pivotally interconnected for translatory movement forwardly and rearwardly with respect to the fifth wheel, guide means for pivoting the rear jaw upwardly to closed position thereof during forward movement of the jaws and for pivoting the rear jaw downwardly to open position thereof during rearward movement of the jaws, a surface on said rear jaw disposed rearwardly of its pivotal connection with the front jaw, said surface extending progressively rearwardly and away from said connection, a member engageable with said surface in fully open position of said rear jaw, and spring means yieldingly urging said member against said surface.

2. In a fifth wheel coupling mechanism; the combination of front and rear jaws, a pivotal connection between said jaws accommodating relative pivotal movement therebetween and interlocking the jaws for translatory movement as a unit with respect to the fifth wheel, guide means for pivoting the rear jaw upwardly to closed position thereof during forward translatory movement of the jaws and for pivoting the rear jaw downwardly to open position thereof during rearward translatory movement of the jaws, a surface on said rear jaw extending progressively rearwardlyand away from said connection, a lock member engageable with a rear wardly facing area of the rear jaw in closed position thereof, said lock member being engageable with said surface when the rear jaw is in its open position, the point of contact between said lock member and said surface being disposed substantially rearwardly of said connection, and spring means for yieldingly urging the closed position during uncoupling and coupling, respectively, with an associated king pin; the

combination of a lock pivoted for movement to locked position with respect to the rear jaw in closed position thereof, and a nose on said lock engageable with an upwardly facing surface of said rear jaw in open position thereof, spring means connected to said lock for urging said nose into engagement with said surface, said surface being disposed rearwardly of the pivotal connection between said jaws and being so formed and arranged that the distance between said surface and said connection is progressively greater rearwardly of said rear jaw, whereby said spring means are effective to positively urge the rear jaw to open position when said nose is engaged with} said surface.

4. In a fifth wheel coupling mechanism having pivotally interconnected front and rear jaws adapted for translatory movement as a unit and having guide means for pivoting the rear jaw to open and closed position during rearward and forward translatory movement of the jaws, respectively; the combination of a lock pivoted for movement to locked engagement with respect to the rear jaw in closed position thereof, a downwardly facing nose on said lock, spring means connected to the lock for urging said nose downwardly, and a cam surface on said rear jaw engageable in fully open position thereof with said lock nose for increasingly stressing the spring means upon each increment of movement of the rear jaw to closed position.

5. In a fifth wheel coupling mechanism having pivotally interconnected front and rear jaws adapted for translatory movement as a unit, and having guide means for pivoting the rear jaw to open and closed positions during rearward and forward translatory movement of the jaws, respectively; the combination of a lock movable to locked engagement with respect to the rear jaw in closed position thereof, a nose on said lock, a, cam surface on said rear jaw engageable in fully open position thereof with said nose, and spring means operatively connected to the lock for urging said nose against said cam surface, said cam surface being formed and arranged to increase stress on said spring means upon movement of the rear jaw from fully open position thereof toward closed position, whereby the spring means yieldingly maintain the rear jaw in said fully open position thereof.

FRANK I-I. KAYLER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,933,622 Fellows Nov. 7, 1933 1,991,507 Ketel Feb. 19, 1935 2,015,313 Kinne Sept. 24, 1935 

